A microwave technology transmits data directly through space, requiring no optical fiber or cable and having an obvious engineering advantage in a city, a remote area, or a special area such as a river. The microwave technology features convenient networking, a flexible use manner, and short service deployment time. As the microwave technology develops, a cost of a microwave device decreases gradually. Therefore, the microwave technology is more and more widely applied.
A co-channel dual polarization (CCDP) transmission technology may implement simultaneous transmission of two orthogonal polarized waves, that is, a horizontal polarized (H) wave and a vertical polarized (V) wave, within the same channel in the space, thereby doubling the service transmission capacity of a single channel. Because a dual polarized signal is affected by a characteristic of a dual-polarized antenna and a spatial transmission environment during transmission, H and V signals reaching a receiver are not completely orthogonal, that is, an H receiver receives a component V′ of the V signal, which causes co-channel interference and may cause a demodulation failure of the receiver in a severe case.
In the prior art, a cross polarization interference cancellation (XPIC) technology is used to eliminate polarization interference by means of interference signal cancellation. In an H direction, for example, a receiving side uses a signal mutually transmitted in a V direction of an XPIC working group to cancel a co-channel interference signal V′ in a receive signal (H+V′) to ensure correct parsing of data in the H direction.
The XPIC working group requires mutual coordination between a sending device and a receiving device in the H and V directions. If one microwave device in the working group is faulty, for example, an indoor unit (IDU) or an outdoor unit (ODU) is faulty, services of the entire XPIC working group may be interrupted.